Thermal surface treatment for reuse of wafers after epitaxial lift off

Abstract

There is disclosed a method of preserving the integrity of a growth substrate in a epitaxial lift-off method, the method comprising providing a structure comprising a growth substrate, one or more protective layers, a sacrificial layer, and at least one epilayer, wherein the sacrificial layer and the one or more protective layers are positioned between the growth substrate and the at least one epilayer; releasing the at least one epilayer by etching the sacrificial layer with an etchant; and heat treating the growth substrate and/or at least one of the protective layers.

What is claimed is: 
     
       1. A method of preserving a growth substrate for subsequent epitaxial growth, comprising:
 providing a structure comprising a growth substrate, one or more protective layers, a sacrificial layer, and at least one epilayer, wherein the sacrificial layer and the one or more protective layers are positioned between the growth substrate and the at least one epilayer; 
 releasing the at least one epilayer by etching the sacrificial layer with an etchant; and 
 heat treating the growth substrate and/or at least one of the protective layers. 
 
     
     
       2. The method of  claim 1 , wherein the growth substrate and at least one of the protective layers are heat treated. 
     
     
       3. The method of  claim 1 , wherein the one or more protective layers are positioned above the growth substrate, and the sacrificial layer is positioned above the one or more protective layers. 
     
     
       4. The method of  claim 2 , wherein the heat treatment is chosen from furnace heating, lamp heating, laser heating, and strip heating. 
     
     
       5. The method of  claim 2 , wherein the heat treatment comprises a rapid thermal processing technique. 
     
     
       6. The method of  claim 5 , wherein the rapid thermal processing technique is rapid thermal annealing. 
     
     
       7. The method of  claim 1 , further comprising etching at least one of the protective layers. 
     
     
       8. The method of  claim 2 , further comprising etching at least one of the protective layers prior to the heat treatment. 
     
     
       9. The method of  claim 2 , wherein the growth substrate comprises a material chosen from Ge, Si, GaAs, InP, GaN, AlN, GaSb, InSb, InAs, and combinations thereof. 
     
     
       10. The method of  claim 2 , wherein the one or more protective layers comprise materials chosen from III-V materials. 
     
     
       11. The method of  claim 2 , wherein the at least one protective layer to be heat treated comprises GaAs. 
     
     
       12. The method of  claim 9 , wherein the one or more protective layers comprise materials chosen from III-V materials. 
     
     
       13. The method of  claim 2 , wherein the growth substrate and at least one of the protective layers comprise the same material. 
     
     
       14. The method of  claim 13 , wherein the growth substrate and the at least one protective layer to be heat treated comprise the same material. 
     
     
       15. The method of  claim 2 , wherein the etchant for releasing the at least one epilayer comprises HF. 
     
     
       16. The method of  claim 2 , wherein the structure further comprises a buffer layer positioned between the at least one epilayer and the growth substrate. 
     
     
       17. The method of  claim 16 , wherein the buffer layer is positioned between the growth substrate and the one or more protective layers. 
     
     
       18. The method of  claim 17 , wherein the growth substrate, the buffer layer, and at least one of the protective layers comprise the same material. 
     
     
       19. The method of  claim 18 , wherein the growth substrate, the buffer layer, and the at least one protective layer to be heat treated comprise the same material. 
     
     
       20. A method of preserving a growth substrate for subsequent epitaxial growth, comprising:
 providing a structure comprising a growth substrate, a first protective layer, a second protective layer, a sacrificial layer, and at least one epilayer, wherein the sacrificial layer and the first and second protective layers are positioned between the growth substrate and the at least one epilayer; 
 releasing the at least one epilayer by etching the sacrificial layer with an etchant; and 
 heat treating the growth substrate and/or at least one of the first and second protective layers.